Studied by 27 peopleDigestive System
breaks down food into small particles that can be absorbed by the body
Alimentary Canal
structures of the digestive system form a "tube" called the...
Mouth, esophagus, stomach, small intestine, gallbladder, pancreas, liver, large intestine
Major structures of the digestive system
Gallbladder, pancreas. liver
accessory organs of the digestive system
Accessory Organs
aid in digestion, but food doesn't pass through them
Mouth
chewing mechanisms digest food, which increases surface area
Esophagus
transports food to stomach via peristalsis
Stomach
churns food and has acidic environment that kills pathogens and activates enzymes
Small intestine
has enzymes that chemically digest biomolecules; wall absobrs small molecules
Liver
secretes bile
Gallbladder
stores and regulates bile
Pancreas
secretes lipase, amylase, and protease
Large intestine
absorbs water and compacts waste to form feces
Peristalsis
a wave of muscle contractions that push food through the gut and mixes it with enzymes
Circular muscles
contract to prevent food from moving backwards
Longitudinal muscles
contract to push food forward down the small intestine tract
Amylase, lipase, protease
enzymes secreted by the pancreas
Starch/glycogen
Substrate of amylase
Maltose
Product of amylase-starch reaction
Triglycerides
Substrate of lipase
Fatty acids and monoglycerides
Product of lipase-triglyceride reaction
Proteins
Substrate of protease
Shorter polypeptides
Product of protease-protein reaction
Be able to label the digestive system
Hydrolysis
Enzymes break macromolecules into monomers that can be absorbed by the intestinal wall. Through what process is this completed?
Proteins
Substrate of peptidase
Amino acids
Product of peptidase-protein reaction
Nucleic acids (DNA?RNA)
Substrate of nuclease
Nucleotides
Product of nuclease-nucleic acids reaction
No. It serves to push substances through the intestine and is the primary component of dietary fiber supplements.
Is cellulose digested?
Absorption
the process of taking substances into cells
The small intestine
Where does absoprtion mostly take place?
Surface area available
What does the rate of absorption depend on?
Villi
finger-like projections of the mucosa that line the inner intestine wall.
A factor of 10
By how much do villi increase surface area?
Thin epithelium and network of capillaries.
Adaptations of the villi that make it suited for absorption
Small intestine
Where do enzymes digest most macromolecules?
Maltose
Substrate of Maltase
Glucose
Product of Maltase-Maltose reaction
Lactose
Substrate of Lactase
Glucose and galactose
Product of lactase-lactose reaction
Sucrose
Substrate of sucrase
Glucose and fructose
Product of sucrase-sucrose reaction
Dipeptides
Substrate of dipeptidase
Amino acids
Product of dipeptidase-dipeptide reaction
Relatively basic (8-14)
What is the optimal pH for digestive enzymes?
Monosaccharides (glucose, fructose, sucrose), amino acids, fatty acids, nitrogenous bases, calcium, potassium, sodium, vitamins
What is absorbed by the villi?
Diffusion
All nutrients except glucose and amino acids enter the villus through the epithelium by ...
Facilitated diffusion
Glucose molecules move into the capillaries by...
Exocytosis
How are lipoproteins excreted?
Mucosa, Sub-mucosa, longitudinal, circular, serosa
Layers of the small intestine
Glucose Transport
Na+/K+ pumps decrease internal concentration of Na+. Na/glucose co-transporters transport glucose into the cells along with Na+. Channel proteins allow glucose to diffuse out of the other side of the cell. Glucose then diffuses into capillaries through small pores.
Glucose absorbed in the capillaries travels to the liver through the hepatic vein. In the liver, cells concert extra glucose into glycogen which can be stored for later use.
How is glucose stores in the liver?
Circulatory system
organ system responsible for transporting oxygen and nutrients around the body as well as removing waste from tissue cells.
Heart
central organ of the ciculatory system
He tied a ligature on the upper arm of a person, which distended the veins in the forearm and made the valves of the forearm clearly visible. He tried to force blood in a vein down the forearm, but to no avail. When he tried to push it up the arm, it moved easilt. Harvey proved that the venous blood flowed to the heart and that the body's valvues in the veins maintained the one-way flow
Outline William Harvey's experiment
Atrium
receives blood from lungs/body
Ventricle
receives blood from an atrium and pumps it out of the heart through arteries
Valves
prevent backward flow
Atrioventricular
between atria and ventricles
Semi-lunar
between ventricles and arteries
Pulmonary artery
carries blood from the heart to the lungs
Pulmonary vein
receives blood back from the lungs
Aorta
carries blood out of the heart to the body
Coronary artery
delivers blood to heart tissue
Vena cava
receives blood from body
Arteries
blood vessels that carry oxygenated blood (expect for pulmonary) away from the heart to cells in the body
High
pressure in arteries
Tunica externa
a tough outer layer of connective tissue
Tunica media
a thick layer containing smooth muscle and elastic fibers
Tunica intima
a smooth endothelium forming the lining of the artery
Elastic fibers recoil after each heart pump, which helps push blood forward. The muscle fibers are able to contract and change the size of the lumen, allowing arteries to control the pressure of blood flowing through them. oth fiber types make arteries "tough," allowing them to withstand high pressures without bulging.
Purpose of muscle and elastic fibers
Capillaries
the smallest blood vessel and form a network through almost all the tissues in the body. Transport and remove substances from cells and so all active cells are close to one.
One cell
How thick is the wall of a capillary?
Yes
Do capillaries have pores?
Veins
transport blood back towards the heart.
Not as high as arteries
Pressure in veins
Valves
Veins contain
Know how to describe blood circulation in the hear
Pulmonary circulation
to and from the lungs
Systemic circulation
to and from all other organs, including heart muscles
Atherosclerosis
occurs when fatty tissues develop in artery walls and muscle walls form a cap over them. This reduces the size of the lumen and impedes blood flow.
Overeating, obesity, diabetes, smoking, stress
Potential causes of atherosclerosis
Coronary Occlsion
occurs when buildup in the artery prevents its ability to deliver oxygen and nutrients. Cases heart pain and increased heart rate.
Sinoatrial node
group of specialized cells that initiates the heartbeat. Located in the right atrium and serves as the heart's pacemaker. This is done without neurons.
Myogenic
the ability to initiate a heartbeat without neurons
Medulla
has a cardiovascular center that is connected to teh heart via two nerves. One signals to decrease the heart rate while the other signals to increase
Blood pressure, oxygen concentration, pH
Heart rate changes depending on...
Epinephrine
secreted by the adrenal glands when vigorous physical activity may be needed and communicate with the SA node
Immune System
organ system responsible for defending the body against infection
Pathogens
cells that are able to cause disease. They are found in the environment and can also live on our skin.
Skin and mucous
What is the body's first line of defense against disease?
Skin
Protects external structures. Thick, dry, and composed predominantly of dead cells. Glands secrete chemicals to restrict bacterial growth.
Mucous
Protects internal structures. Thin region composed of living cells that secrete fluid (mucous) to trap pathogens (which may then be removed)
Platelets
small cell fragments that flow in the blood. When the skin is cut, they gather at the damaged site. They then release clotting factors, which initiate the blood clotting process.
Thrombin
What is prothrombin activated into when clotting factors are released?
Fibrin
What does thrombin convert fibrinogen into?
Fibrin
Insoluble and forms a mesh at the wound site where the platelets are
Red blood cells and small particles getting stuck
What creates the "gel" that seals the wound?
Coronary thrombosis
a blood clot that forms in the coronary artery. As a result, tissues in the heart wall do not receive enough oxygen or nutrients
Note
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